Extrinsic Camera Calibration Using Diffractive Optical Elements
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Solution Overview
Problem
Existing camera calibration methods for augmented and virtual reality systems are inefficient and cumbersome, particularly when multiple cameras are involved, as they require extensive individual intrinsic calibration and do not effectively address extrinsic parameters.
Innovation Solution
The use of diffractive optical elements (DOEs) for simultaneous extrinsic calibration of multiple cameras, determining both extrinsic and intrinsic parameters of cameras and DOEs, allowing for accurate reconstruction of real-world objects in virtual or augmented reality environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional individual intrinsic calibration methods are used for multiple cameras, then each camera can be calibrated, but the calibration process becomes extensive and cumbersome
Solution Approach 1:
The patent combines intrinsic calibration and extrinsic calibration into a single unified calibration process. Multiple cameras are calibrated simultaneously using a common calibration target, merging what would traditionally be separate calibration operations into one efficient process that reduces total calibration time while maintaining accuracy.
Solution Approach 2:
The calibration target serves multiple functions: it enables intrinsic parameter calibration for each camera, extrinsic parameter calibration between cameras, and provides a unified reference frame for all cameras. This multi-functional approach eliminates the need for separate calibration procedures.
2Measurement precision
If conventional calibration methods are used, then individual camera parameters can be determined, but extrinsic parameters between multiple cameras are not effectively addressed
Solution Approach 1:
The patent merges intrinsic and extrinsic calibration into a single simultaneous process. The calibration target is designed to provide reference information that enables determination of both intrinsic parameters (focal length, principal point) and extrinsic parameters (relative position and orientation between cameras) in one unified calibration procedure.
3Reliability
If multiple separate calibration procedures are performed, then comprehensive calibration data can be obtained, but the complexity of the calibration process increases
Solution Approach 1:
A single calibration target is designed to provide all necessary reference information for both intrinsic and extrinsic calibration of multiple cameras. The target includes patterns and features that enable simultaneous determination of all calibration parameters, eliminating the need for multiple separate calibration procedures and their associated complexities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables efficient and accurate calibration of multiple cameras by reducing the number of required images and simplifying the calibration process, facilitating precise 3D reconstruction and object location determination in AR/VR systems.
Implementation Method 1
Each DOE in the plurality of DOEs modulates an input light beam to generate a predetermined pattern of light beams
Data Source
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AI summary
Determining extrinsic parameters of a plurality of cameras using a plurality of diffractive optical elements, comprising: providing (S902) a plurality of diffractive optical elements (502, 504); providing (S904) a plurality of cameras (402, 404) positioned in an eye box of each one of the plurality of diffractive optical elements; receiving (S906) a plurality of images from the plurality of cameras, wherein a single image is received from each one of the plurality of cameras at a given position with respect to one of the plurality of diffractive optical elements; for each image, identifying (S908) data pairs, each data pair including pixel coordinates of an intensity peak in the image and virtual light source produced by the diffractive optical element that corresponds to the intensity peak; and determining (S910) extrinsic parameters of the plurality of cameras using the identified data pairs and a predetermined transform matrix of the plurality of diffractive optical elements.